To the Editor.—In the discussion of the increase of suicide rates in various countries, reference was made to the hypothesis that part of the variance in the increase might be attributable to an increasing suicide risk of successive birth cohorts, in particular among men. Increased suicide rates in all age groups among successive birth cohorts were first reported in Canada.1 Then, the same phenomenon, in reduced magnitude, was found in the United States.2 Boyd,3 however, pointed out that this finding might be due to an artifact created by different diagnostic criteria and a changing stability of the classification of suicides over time. Thus, Murphy4 has commented "that it will be of interest to learn what the experience has been in other countries over the same time period." Meanwhile, similar results have been reported in Australia5 that are significant only for the age groups from